The use of asphalt-polymer blends is well known in the art. Such asphalt-polymer blends are used on road surfaces, structural waterproofing materials and the like. The incorporation of polymers into asphalts modifies the properties of the asphalt and thereby improves the physical properties of the asphalt (e.g., improved flow (creep) temperature, reduction in the stiffening (cracking) temperature, improved elongation, improve tensile strength, improved tear strength, etc.).
Many of the asphalt polymer blends include the use of a surfactant that is mixed by standard techniques with the asphalt and polymer. Depending on the type of emulsifier used during the preparation of the asphalt emulsion, the asphalt emulsions may be an anionic aqueous emulsion or a cationic aqueous emulsion. Anionic emulsions are commonly used in building and waterproofing applications. In particular, anionic asphalt emulsions are commonly used in roofing membranes. Cationic emulsions are commonly used as a binder in the construction or repair of road pavements.
U.S. Pat. No. 4,724,245, which is incorporated herein, discloses a method that consists in preparing a blend of asphalt and hydroxytelechelic polybutadiene (HTBD), and emulsifying the blend in an aqueous phase and then causing cross-linking to take place by addition of polyisocyanate dispersed in an aqueous phase.
U.S. Pat. No. 3,909,474, which is incorporated herein, discloses a similar method of fowling an asphalt as disclosed in the '245 patent. The asphalt used in the '474 patent is a preoxidized asphalt, and the cross-linking is achieved by oxidation of the HTBD.
U.S. Pat. No. 3,932,331, which is incorporated herein, discloses a method for rapidly breaking and hardening an asphalt emulsion by incorporating therein an isocyanate (NCO)-terminated urethane prepolymer.
DE 40939151 discloses a composition obtained by the reaction of a prepolymer with a dispersion of an unsaturated olefin compound, of polyurethane or of asphalt.
DE 4408154 discloses a coating based on an asphalt emulsion containing a polyurethane prepolymer with NCO terminal groups.
Many of the prior art compositions require the use of reactive two-component compositions with the necessary presence of an isocyanate component in order to achieve satisfactory performance.
United States Patent Publication No. 2005/0124736 filed Jun. 9, 2005, which is incorporated herein, discloses an asphalt emulsion based on an aqueous polymer composition equivalent to a non-reactive one-component composition.